Henry's Defence of the Seven Sacraments (Assertio Septem Sacramentorum) is available online at Google Books, in both English and Latin. Just type in "Defence of the Seven Sacraments" and it should be the first one that comes up. You'll have to leaf through the various whistles and bells that adorn the edition, including "Henry's Letter to Leo," "Oration of Dr. John Clerk," etc., but you do get finally to the Assertio in full.

Per Henry's speeches, I can only think of three events in which he made actual recorded formal speeches - his valedictory address to Parliament, noted by Lara; his explanation of his reasons for seeking an annulment of his first marriage, delivered to a select audience of influential opinion-makers invited to Bridewell in 1528; and his address to the legatine court at Blackfriars in 1529, recapitulating much of the Bridewell arguments. You can find these speeches in their authentic "ye olde English" in Hall's Chronicle, which is a wealth of information on Henry's interactions with various parties, mostly not in lengthy formal oration but memorable remarks nonetheless. Hall's Chronicle is available not on Google Books, but on Google (just type "Hall's Chronicle" into the browser). The site lets you choose the format you want to read the Chronicle in, pdf, plain text, actual book format, etc.

Edward Hall - an eyewitness to Henry VIII's reign - starts with Henry IV, so you'll have to be persistent and leaf through to "Henry the VIIJ." as the reign of Henry VIII is rendered. Hall did not specify actual calendar years like 1528 or 1545, but rather regnal years, such as "The XX. Yere of," etc. (that's 1528, to you). The language and spelling are challenging but the source does give you the authentic flavor of Henrician England.